Carboxylated detergent- disperant additive for lubricating oils

ABSTRACT

The present invention provides a novel unsulfurized, carboxylate-containing additive for lubricating oils, comprising a mixture of alkaline earth metal salts (hydrocarbyl phenate/hydrocarbyl salicylate) and a reduced amount of unreacted hydrocarbyl phenols, as well as additive packages, concentrates and finished oil compositions comprising the same. Specifically, it relates to additives comprising said mixture in which said hydrocarbyl salicylate is primarily single-aromatic-ring hydrocarbyl salicylate. The invention also provides a method for producing said additive.

FIELD OF THE INVENTION

The present invention relates to a novel unsulfurized,carboxylate-containing additive for lubricating oils, comprising amixture of alkaline earth metal salts (hydrocarbyl phenate/hydrocarbylsalicylate) and a reduced amount of unreacted hydrocarbyl phenols, aswell as additive packages, concentrates and finished oil compositionscomprising the same. Specifically, it relates to additives comprisingsaid mixture in which said hydrocarbyl salicylate is primarilysingle-aromatic-ring hydrocarbyl salicylate. This additive improvesantioxidant properties, high temperature deposit control, BN retention,corrosion control and black sludge control in lubricating oils. Thisinvention is also directed, in part, to methods of preparing and usingsaid novel additive.

BACKGROUND OF THE INVENTION

The preparation of hydrocarbyl phenates and hydrocarbyl salicylates iswell known in the art.

U.S. Pat. No. 3,036,971 discloses preparing detergent dispersantadditives based on sulfurized alkylphenates of high basicity alkalineearth metals. These additives are prepared by sulfurization of analkylphenol, neutralization of the sulfurized alkylphenol with analkaline earth metal base, then super-alkalization by carbonation of thealkaline earth metal base dispersed in the sulfurized alkylphenate.

French patent 1,563,557 discloses detergent additives based onsulfurized calcium alkylsalicylates. These additives are prepared bycarboxylation of a potassium alkylphenate, exchange with calciumchloride, then sulfurization of the calcium alkylsalicylate obtainedwith sulfur in the presence of lime, a

French patent application 2,625,220 discloses superalkalizeddetergent-dispersant additives based on alkylphenates andalkylsalicylates. These additives are prepared by neutralization of analkylphenol with an alkaline earth metal base in the presence of an acidand a solvent, distillation of the solvent, carboxylation, sulfurizationand superalkalization by sulfur and an alkaline earth metal base in thepresence of glycol and solvent, followed by carbonation and filtration.

PCT Patent Application Publication No. WO 95/25155 discloses a processthat is able to improve substantially the performance of theseadditives, particularly in the tests relating to foaming, compatibilityand dispersion in a new oil, and in the tests of stability towardshydrolysis. This process comprises neutralization with alkaline earthmetal base of a mixture of linear and branched alkylphenols in thepresence of a carboxylic acid, carboxylation by the action of carbondioxide of the alkylphenate, followed by sulfurization andsuper-alkalization, then carbonation, distillation, filtration, anddegasing in air.

European Patent Application Publication No. 0933417 discloses anunsulfurized, alkali metal-free detergent-dispersant additive,comprising a mixture of alkaline earth metal salts(alkylphenate/alkylsalicylate) and unreacted alkylphenol. This additiveimproves antioxidant propties, high temperature deposit control, andblack sludge control.

U.S. Pat. Nos. 6,162,770 and 6,262,001 teach an unsulfurized, alkalimetal-free, detergent-dispersant composition having from 40% to 60%alkylphenol, from 10% to 40% alkaline earth alkylphenate, and from 20%to 40% alkaline earth single-aromatic-ring alkylsalicylate, and aprocess for preparing the same. This composition may have an alkalineearth double-aromatic-ring alkylsalicylate as long as the mole ratio ofsingle-ring alkylsalicylate to double-aromatic-ring alkylsalicylate isat least 8:1. This composition may be produced by the three-step processinvolving neutralization of alkylphenols, carboxylation of the resultingalkylphenate, and filtration of the product of the carboxylation step.The detergent-dispersant produced by the method can be used in an enginelubricating composition to improve antioxidant properties, hightemperature deposit control, and black sludge control.

SUMMARY OF THE INVENTION

The present invention provides a novel unsulfurized,carboxylate-containing additive for lubricating oils, comprising amixture of alkaline earth metal salts (hydrocarbyl phenate/hydrocarbylsalicylate) and a reduced amount of unreacted hydrocarbyl phenols, aswell as additive packages, concentrates and finished oil compositionscomprising the same. Specifically, it relates to additives comprisingsaid mixture in which said hydrocarbyl salicylate is primarilysingle-aromatic-ring hydrocarbyl salicylate.

The present invention also provides a method for producing the abovedescribed additive, which comprises the neutralization of hydrocarbylphenol using an alkaline earth base in the presence of a promoter toproduce a hydrocarbyl phenate. Preferably, said promoter comprises atleast one carboxylic acid containing from one to four carbon atoms, andsaid neutralization step is carried out in the absence of alkali base,in the absence of dialcohol, and in the absence of monoalcohol. Theneutralization step is followed by carboxylation of the hydrocarbylphenate produced in the neutralization step; and separation of thestarting hydrocarbyl phenols from the product of the carboxylation step.

The hydrocarbyl phenols may comprise a mixture of linear and/or branchedhydrocarbyl constituents. For example, the hydrocarbyl phenols may bemade up entirely of linear hydrocarbyl phenol, entirely of branchedhydrocarbyl phenol, or a mixture of both. Preferably, the hydrocarbylphenols contain up to 85% of linear hydrocarbyl phenol in mixture withat least 15% of branched hydrocarbyl phenol in which the branchedhydrocarbyl radical contains at least nine carbon atoms. Morepreferably, the hydrocarbyl phenols are alkylphenols which contain from35% to 85% of linear alkylphenol in mixture with from 15% to 65% ofbranched alkylphenol. The ratio of branched versus linear alkylphenol isgiven by weight. Preferably, the linear hydrocarbyl radical contains 12to 40 carbon atoms, more preferably from 18 to 30 carbon atoms, and, ifbranched hydrocarbyl phenols are present, the branched hydrocarbylradical contains at least 9 carbon atoms, preferably from 9 to 24 carbonatoms, more preferably 10 to 15 carbon atoms.

Preferably, the alkaline earth base is selected from the groupconsisting of calcium oxide, calcium hydroxide, magnesium oxide, andmixtures thereof.

Preferably, the carboxylic acid is a mixture of formic acid and aceticacid, more preferably a 50/50 by weight mixture of formic and aceticacid.

Preferably, the neutralization step is carried out at a temperature ofat least 200° C., more preferably at least 215° C. The pressure isreduced gradually below atmospheric in order to remove the water ofreaction, in the absence of any solvent that may form an azeotrope withwater. Preferably, the quantities of reagents used correspond to thefollowing molar ratios:

-   -   (1) alkaline earth base/alkylphenol of from 0.2:1 to 0.7:1, more        preferably from 0.3:1 to 0.5:1; and    -   (2) carboxylic acid/alkylphenol of from 0.01:1 to 0.5:1, more        preferably from 0.03:1 to 0.15:1.

In one embodiment, the neutralization step is carried out at atemperature of at least 240° C. with a gradual reduction in pressurebelow atmospheric so as to reach a pressure of no more than 7,000 Pa (70mbars) at 240° C.

The hydrocarbyl phenate obtained in the neutralization step iscarboxylated in order to convert at least 20 mole % of the startinghydrocarbyl phenols to hydrocarbyl salicylate using carbon dioxide undercarboxylation conditions. Preferably, at least 22 mole % of the startinghydrocarbyl phenols is converted, and this conversion occurs at atemperature between 180° C. and 240° C., under a pressure within therange of from above atmospheric pressure to 15×10⁵ Pa (15 bars) for aperiod of one to eight hours.

More preferably, the starting hydrocarbyl phenols are alkylphenols andat least 25 mole % of the starting alkylphenols is converted toalkylsalicylate using carbon dioxide at a temperature equal to orgreater than 200° C., under a pressure of 4×10⁵ Pa (4 bars).

The hydrocarbyl salicylate produced in the carboxylation stepcarboxylation step may comprise both single-aromatic-ring hydrocarbylsalicylate and double-aromatic-ring hydrocarbyl salicylate. Preferably,the mole ratio of single-aromatic-ring hydrocarbyl salicylate todouble-aromatic-ring hydrocarbyl salicylate is at least 8:1.

Preferably, the product of the carboxylation step is then filtered toremove any sediment formed in the carboxylation step.

The product of the carboxylation step is then subjected to a separationprocedure such as solvent extraction, distillatioin, membranefiltration, and the like wherein at least about 10% of the startinghydrocarbyl phenols are separated from the product of the carboxylationstep. Preferably, at least about 30% to about 55% of the startinghydrocarbyl phenols are separated. More preferably, at least about 45%to about 50% of the starting hydrocarbyl phenols are separated from theproduct of the carboxylation step.

Once the starting hydrocarbyl phenols are separated from the product ofthe carboxylation step, said hydrocarbyl phenols may advantageously berecycled to be used as starting materials in the process of the presentinvention or in any other process.

Preferably, the separation step is performed via distillation, morepreferably via falling film distillation or short path distillation,most preferably via wiped film evaporator distillation. Saiddistillation is carried out at a temperature of from about 150° C. toabout 250° C. and at a pressure of about 0.1 to about 4 mbar; morepreferably from about 190° C. to about 230° C. and at about 0.5 to about3 mbar; most preferably from about 195° C. to about 225° C. and at apressure of about 1 to about 2 mbar.

The unsulfurized, carboxylate-containing additive of the presentinvention may advantageously be blended with an effective viscosityimproving amount of organic diluent. Preferably, enough diluent is addedso that said diluent makes up from about 10% to about 80% by weight ofthe blended product. More preferably, said diluent makes up from about20% to about 50% by weight of the blended product. Suitable diluentsinclude Group 1 or Group 2 base oils such as 100N base oil; organicsolvents such as pentane, heptane, benzene, toluene and the like; andother suitable organic compounds such as hydrocarbyl phenols which mayadvantageously be recycled from the distillation step of the presentinvention.

The unsulfurized, carboxylate-containing additive produced by thismethod has the following composition:

-   -   (a) less than 40% hydrocarbyl phenol,    -   (b) 10% to 50% alkaline earth metal hydrocarbyl phenate,    -   (c) 15% to 60% alkaline earth metal single-aromatic-ring        hydrocarbyl salicylate, and    -   (d) 0% to 50% organic diluent.

In one embodiment, the unsulfurized carboxylate-containing additivecomprises from 0 to 35% hydrocarbyl phenol; preferably from 0 to 30%hydrocarbyl phenol; more preferably from 0 to 20% hydrocarbyl phenol;most preferably from 0 to 15%/1 hydrocarbyl phenol.

The unsulfurized, carboxylate-containing additive may also comprise analkaline earth metal double-aromatic-ring hydrocarbyl salicylate, butthe mole ratio of single-aromatic-ring hydrocarbyl salicylate todouble-aromatic-ring hydrocarbyl salicylate will be at least 8:1.

The unsulfurized, carboxylate-containing additive produced by the methodof the present invention can be used in an engine lubricating oilcomposition containing a major part of lubricating oil, from 1% to 30%of the unsulfurized, carboxylate-containing additive of the presentinvention, and preferably at least one other additive. Examples of otheradditives that may be used include metal-containing detergents, ashlessdispersants, oxidation inhibitors, rust inhibitors, demulsifiers,extreme pressure agents, friction modifiers, multifunctional additives,viscosity index improvers, pour point depressants, and foam inhibitors.

The unsulfurized, carboxylate-containing additive produced by the methodof the present invention has been found to be particularly useful whenused in an engine lubricating oil composition in combination with atleast one of the following: a phenate, a phenate-stearate, a salicylate,and a carboxy-stearate. Preferably, the mass ratio of phenate tounsulfurized, carboxylate-containing additive in said composition isfrom 1:0.035 to 1:98; more preferably from 1:0.239 to 1:14; mostpreferably from 1:0.451 to 1:7.5. Preferably, the mass ratio ofphenate-stearate to unsulfurized, carboxylate-containing additive insaid composition is from 1:0.051 to 1:126; more preferably from 1:0.353to 1:12; most preferably from 1:0.667 to 1:97. Preferably, the massratio of salicylate to unsulfurized, carboxylate-containing additive insaid composition is from 1:0.026 to 1:120; more preferably from 1:0.178to 1:17; most preferably from 1:0.335 to 1:9.2. Preferably, thesalicylate is a high-overbased salicylate. Preferably, the mass ratio ofcarboxy-stearate to unsulfurized, carboxylate-containing additive insaid composition is from 1:0.023 to 1:105; more preferably from 1:0.156to 1:15; most preferably from 1:0.294 to 1:8.1.

In marine applications, the black sludge deposit control, hightemperature deposit control, viscosity increase control anddemulsibility performance of a lubricating oil can be improved by addingto the lubricating oil an effective amount of the unsulfurized,carboxylate-containing additive of the present invention.

In automotive applications, the high temperature deposit controlperformance, corrosion control and oxidation inhibition performance of alubricating oil can be improved by adding to the lubricating oil aneffective amount of the unsulfurized, carboxylate-containing additive ofthe present invention.

The invention also provides a hydraulic oil composition with improvedfilterability containing a base oil of lubricating viscosity, from 0.1%to 6% of the unsulfurized, carboxylate-containing additive of thepresent inventions, and preferably at least one other additive,

The invention also provides a concentrate comprising the unsulfurized,carboxylate-containing additive of the present invention, an organicdiluent, and preferably at least one other additive. The organic diluentconstitutes from 20% to 80% of the concentrate. Examples of otheradditives that may be used include metal-containing detergents, ashlessdispersants, oxidation inhibitors, rust inhibitors, demulsifiers,extreme pressure agents, friction modifiers, multifunctional additives,viscosity index improvers, pour point depressants, and foam inhibitors.

DETAILED DESCRIPTION OF THE INVENTION

In its broadest aspect, the present invention provides an unsulfurized,carboxylate-containing additive comprising hydrocarbyl phenol, alkalineearth metal hydrocarbyl phenate, and alkaline earth metalsingle-aromatic-ring hydrocarbyl salicylate useful for improving BNretention, corrosion performance, bulk oxidation, high temperaturedeposit control, black sludge control, thermal oxidation stability, andother properties of a lubricating oil.

Prior to discussing the invention in further detail, the following termswill be defined:

Definitions

As used herein the following terms have the following meanings unlessexpressly stated to the contrary:

The term “hydrocarbyl” means an alkyl or alkenyl group.

The term “metal” means alkali metals, alkaline earth metals, or mixturesthereof.

The term “alkaline earth metal” means calcium, barium, magnesium,strontium, or mixtures thereof.

The term “salicylate” means a metal salt of a salicylic acid.

The term “alkaline earth metal single-aromatic-ring hydrocarbylsalicylate” means an alkaline earth metal salt of a hydrocarbylsalicylic acid, wherein there is only one hydrocarbyl salicylic anionper each alkaline earth metal base cation.

The term “alkaline earth metal single-aromatic-ring alkylsalicylate”means an alkaline earth metal single-aromatic-ring hydrocarbylsalicylate wherein the hydrocarbyl group is an alkyl group.

The term “alkaline earth metal double-aromatic-ring hydrocarbylsalicylate” means an alkaline earth metal salt of a hydrocarbylsalicylic acid, wherein there are two hydrocarbyl salicylic anions pereach alkaline earth metal base cation.

The term “alkaline earth metal double-aromatic-ring alkylsalicylate”means an alkaline earth metal double-aromatic-ring hydrocarbylsalicylate wherein the hydrocarbyl groups are alkyl groups.

The term “hydrocarbyl phenol” means a phenol having one or morehydrocarbyl substituents; at least one of which has a sufficient numberof carbon atoms to impart oil solubility to the phenol.

The term “alkylphenol” means a phenol having one or more alkylsubstituents, wherein at least one of the alkyl substituents has asufficient number of carbon atoms to impart oil solubility to thephenol.

The term “phenate” means a metal salt of a phenol.

The term “hydrocarbyl phenate” means a metal salt of a hydrocarbylphenol.

The term “alkaline earth metal hydrocarbyl phenate” means an alkalineearth metal salt of a hydrocarbyl phenol.

The term “alkaline earth metal alkylphenate” means an alkaline earthmetal salt of an alkylphenol.

The term “phenate-stearate” means a phenate that has been treated withstearic acid or anhydride or salt thereof.

The term “long-chain carboxylic acid” means a carboxylic acid having analkyl group having an average carbon number of from 13 to 28. The alkylgroup may be linear, branched, or mixtures thereof.

The term “carboxy-stearate” means an alkaline earth metalsingle-aromatic-ring hydrocarbyl salicylate that has been treated with along-chain carboxylic acid, anhydride or salt thereof.

The term “Base Number” or “BN” refers to the amount of base equivalentto milligrams of KOH in one gram of sample. Thus, higher BN numbersreflect more alkaline products, and therefore a greater alkalinityreserve. The BN of a sample can be determined by ASTM Test No. D2896 orany other equivalent procedure.

Unless otherwise specified, all percentages are in weight percent.

single aromatic ring hydrocarbyl salicylate

double aromatic ring hydrocarbyl salicylatePreparation of the Lubricant Additive CompositionA. Neutralization Step

In the first step, hydrocarbyl phenols are neutralized in the presenceof a promoter. In one embodiment, said hydrocarbyl phenols areneutralized using an alkaline earth metal base in the presence of atleast one C₁ to C₄ carboxylic acid. Preferably, this reaction is carriedout in the absence of alkali base, and in the absence of dialcohol ormonoalcohol.

The hydrocarbyl phenols may contain up to 100% linear hydrocarbylgroups, up to 100% branched hydrocarbyl groups, or both linear andbranched hydrocarbyl groups. Preferably, the linear hydrocarbyl group,if present, is alkyl, and the linear alkyl radical contains 12 to 40carbon atoms, more preferably 18 to 30 carbon atoms. The branchedhydrocarbyl radical, if present, is preferably alkyl and contains atleast nine carbon atoms, preferably 9 to 24 carbon atoms, morepreferably 10 to 15 carbon atoms. In one embodiment, the hydrocarbylphenols contain up to 85% of linear hydrocarbyl phenol (preferably atleast 35% linear hydrocarbyl phenol) in mixture with at least 15% ofbranched hydrocarbyl phenol.

The use of an alkylphenol containing at least 35% of long-chain linearalkylphenol (from 18 to 30 carbon atoms) is particularly attractivebecause a long linear alkyl chain promotes the compatibility andsolubility of the additives in lubricating oils. However, the presenceof relatively heavy linear alkyl radicals in the alkylphenols can makethe latter less reactive than branched alkylphenols, hence the need touse harsher reaction conditions to bring about their neutralization byan alkaline earth metal base.

Branched alkylphenols can be obtained by reaction of phenol with abranched olefin, generally originating from propylene. They consist of amixture of monosubstituted isomers, the great majority of thesubstituents being in the para position, very few being in the orthoposition, and hardly any in the meta position. That makes themrelatively more reactive towards an alkaline earth metal base, since thephenol function is practically devoid of steric hindrance.

On the other hand, linear alkylphenols can be obtained by reaction ofphenol with a linear olefin, generally originating from ethylene. Theyconsist of a mixture of monosubstituted isomers in which the proportionof linear alkyl substituents in the ortho, para, and metal positions ismore uniformly distributed. This makes them less reactive towards analkaline earth metal base since the phenol function is less accessibledue to considerable steric hindrance, due to the presence of closer andgenerally heavier alkyl substituents. Of course, linear alkylphenols maycontain alkyl substituents with some branching which increases theamount of para substituents and, resultantly, increases the relativereactivity towards alkaline earth metal bases.

The alkaline earth metal bases that can be used for carrying out thisstep include the oxides or hydroxides of calcium, magnesium, barium, orstrontium, and particularly of calcium oxide, calcium hydroxide,magnesium oxide, and mixtures thereof. In one embodiment, slaked lime(calcium hydroxide) is preferred.

The promoter used in this step can be any material that enhancesneutralization. For example, the promoter may be a polyhydric alcohol,dialcohol, monoalcohol, ethylene glycol or any carboxylic acid.Preferably, a carboxylic acid is used. More preferably, C₁ to C₄carboxylic acids are used in this step including, for example, formic,acetic, propionic and butyric acid, and may be used alone or in mixture.Preferably, a mixture of acids is used, most preferably a formicacid/acetic acid mixture. The molar ratio of formic acid/acetic acidshould be from 0.2:1 to 100:1, preferably between 0.5:1 and 4:1, andmost preferably 1:1. The carboxylic acids act as transfer agents,assisting the transfer of the alkaline earth metal bases from a mineralreagent to an organic reagent.

The neutralization operation is carried out at a temperature of at least200° C., preferably at least 215° C., and more preferably at least 240°C. The pressure is reduced gradually below atmospheric in order todistill off the water of reaction. Accordingly the neutralization shouldbe conducted in the absence of any solvent that may form an azeotropewith water. Preferably, the pressure is reduced to no more than 7,000 Pa(70 mbars).

The quantities of reagents used should correspond to the following molarratios:

-   -   (1) alkaline earth metal base/hydrocarbyl phenol of 0.2:1 to        0.7:1, preferably 0.3:1 to 0.5:1; and    -   (2) carboxylic acid/hydrocarbyl phenol of 0.01:1 to 0.5:1,        preferably from 0.03:1 to 0.15:1.

Preferably, at the end of this neutralization step the hydrocarbylphenate obtained is kept for a period not exceeding fifteen hours at atemperature of at least 215° C. and at an absolute pressure of between5,000 and 10⁵ Pa (between 0.05 and 1.0 bar). More preferably, at the endof this neutralization step the hydrocarbyl phenate obtained is kept forbetween two and six hours at an absolute pressure of between 10,000 and20,000 Pa (between 0.1 and 0.2 bar).

By providing that operations are carried out at a sufficiently hightemperature and that the pressure in the reactor is reduced graduallybelow atmospheric, the neutralization reaction is carried out withoutthe need to add a solvent that forms an azeotrope with the water formedduring this reaction.

B. Carboxylation Step

The carboxylation step is conducted by simply bubbling carbon dioxideinto the reaction medium originating from the preceding neutralizationstep and is continued until at least 20 mole % of the startinghydrocarbyl phenols is converted to hydrocarbyl salicylate (measured assalicylic acid by potentiometric determination). It must take placeunder pressure in order to avoid any decarboxylation of thealkylsalicylate that forms.

Preferably, at least 22 mole % of the starting hydrocarbyl phenols isconverted to hydrocarbyl salicylate using carbon dioxide at atemperature of between 180° C. and 240° C., under a pressure within therange of from above atmospheric pressure to 15×10⁵ Pa (15 bars) for aperiod of one to eight hours.

According to one variant, at least 25 mole % of the starting hydrocarbylphenols is converted to hydrocarbyl salicylate using carbon dioxide at atemperature equal to or greater than 200° C. under a pressure of 4×10⁵Pa (4 bars).

C. Filtration Step

The product of the carboxylation step may advantageously be filtered.The purpose of the filtration step is to remove sediments, andparticularly crystalline calcium carbonate, which might have been formedduring the preceding steps, and which may cause plugging of filtersinstalled in lubricating oil circuits.

D. Separation Step

At least 10% of the starting hydrocarbyl phenol is separated from theproduct of the carboxylation step. Preferably, the separation isaccomplished using distillation. More preferably, the distillation iscarried out in a wiped film evaporator at a temperature of from about150° C. to about 250° C. and at a pressure of about 0.1 to about 4 mbar;more preferably from about 190° C. to about 230° C. and at about 0.5 toabout 3 mbar; most preferably from about 195° C. to about 225° C. and ata pressure of about 1 to about 2 mbar. At least 10% of the startinghydrocarbyl phenol is separated. More preferably, at least 30% of thestarting hydrocarbyl phenol is separated. Most preferably, up to 55% ofthe starting hydrocarbyl phenol is separated. The separated hydrocarbylphenol may then be recycled to be used as starting materials in thenovel process or in any other process.

Unsulfurized, Carboxylate-Containing Additive

The unsulfurized, carboxylate-containing additive formed by the presentprocess can be characterized by its unique composition, with much morealkaline earth metal single-aromatic-ring hydrocarbyl salicylate andless hydrocarbyl phenol than produced by other routes. When thehydrocarbyl group is an alkyl group, the unsulfurized,carboxylate-containing additive has the following composition;

-   -   (a) less than 40% alkylphenol,    -   (b) from 10% to 50% alkaline earth metal alkylphenate, and    -   (b) from 15% to 60% alkaline earth metal single-aromatic-ring        alkylsalicylate.

Unlike alkaline earth metal alkylsalicylates produced by other process,this unsulfurized, carboxylate-containing additive composition can becharacterized by having only minor amounts of an alkaline earth metaldouble-aromatic-ring alkylsalicylates. The mole ratio ofsingle-aromatic-ring alkylsalicylate to double-aromatic-ringalkylsalicylate is at least 8:1.

Characterization of the Product by Infrared Spectrometry

Out-of-aromatic-ring-plane C—H bending vibrations were used tocharacterize the unsulfurized carboxylate-containing additive of thepresent invention. Infrared spectra of aromatic rings show strongout-of-plane C—H bending transmittance band in the 675-870 cm⁻¹ region,the exact frequency depending upon the number and location ofsubstituents. For ortho-disubstituted compounds, transmittance bandoccurs at 735-770 cm⁻¹. For para-disubstituted compounds, transmittanceband occurs at 810-840 cm⁻¹.

Infrared spectra of reference chemical structures relevant to thepresent invention indicate that the out-of-plane C—H bendingtransmittance band occurs at 750±3 cm⁻¹ for ortho-alkylphenols, at 760±2cm⁻¹ for salicylic acid, and at 832±3 cm⁻¹ for para-alkylphenols.

Alkaline earth alkylphenates known in the art have infrared out-of-planeC—H bending transmittance bands at 750±3 cm⁻¹ and at 832±3 cm⁻¹.Alkaline earth alkylsalicylates known in the art have infraredout-of-plane C—H bending transmittance bands at 763±3 cm⁻¹ and at 832±3cm⁻¹.

The unsulfurized carboxylate-containing additive of the presentinvention shows essentially no out-of-plane C—H bending vibration at763±3 cm⁻¹, even though there is other evidence that alkylsalicylate ispresent. This particular characteristic has not been fully explained.However, it may be hypothesized that the particular structure of thesingle aromatic ring alkylsalicylate prevents in some way thisout-of-plane C—H bending vibration. In this structure, the carboxylicacid function is engaged in a cyclic structure, and thus may generateincreased steric hindrance in the vicinity of the aromatic ring,limiting the free motion of the neighbor hydrogen atom. This hypothesisis supported by the fact that the infrared spectrum of the acidifiedproduct (in which the carboxylic acid function is no longer engaged in acyclic structure and thus can rotate) has an out-of-plane C—Htransmittance band at 763±3 cm⁻¹.

The unsulfurized carboxylate-containing additive of the presentinvention can thus be characterized by having a ratio of infraredtransmittance band of out-of-plane C—H bending at about 763±3 cm⁻¹ toout-of-plane C—H bending at 832±3 cm⁻¹ of less than 0.1:1.

The unsulfurized, carboxylate-containing additive formed by this method,being non-sulfurized, would provide improved high temperature depositcontrol performance over sulfurized products. Being alkali-metal free,this additive can be employed as a detergent-dispersant in applications,such as marine engine oils, where the presence of alkali metals haveproven to have harmful effects.

Detergents

The unsulfurized, carboxylate-containing additive formed by the processdescribed above has been found to provide improved bulk oxidation andcorrosion control performance when combined with other additives,including detergents.

detergents help control varnish, ring zone deposits, and rust by keepinginsoluble particles in colloidal suspension. Metal-containing (orash-forming detergents) function both as detergents to control deposits,and as acid neutralizers or rust inhibitors, thereby reducing wear andcorrosion and extending engine life. Detergents generally comprise apolar head with a long hydrophobic tail; with the polar head comprisinga metal salt of an acidic organic compound. The salts may contain asubstantially stoichiometric amount of the metal in which case they areusually described as normal or neutral salts, and would typically have atotal base number (as measured by ASTM D2896) of from 0 to 10. It ispossible to include large amounts of a metal base by reacting an excessof a metal compound such as an oxide or hydroxide with an acidic gassuch as carbon dioxide to form an overbased detergent. Such overbaseddetergents may have a total base number of about 15 to 30 (lowoverbased); 31 to 170 (medium overbased); 171 to 400 (high overbased);or about 400 (high-high overbased).

Detergents that may be used include phenates, overbased phenates andsulfurized phenates; phenate-carboxylates, and overbasedphenate-carboxylates; carboxy-stearates and overbased carboxy-stearates;and low, medium and high overbased salicylates. Suitable metals includethe alkali or alkaline earth metals, e.g., sodium, potassium, lithium,calcium, and magnesium. The most commonly used metals are calcium andmagnesium, which may both be present in detergents used in a lubricant.

Preparation of Phenates

The phenates which may be used in the present invention are typicallyhydrocarbyl substituted phenates in which the hydrocarbyl substituent orsubstituents of the phenate are preferably one or more alkyl group,either branched or unbranched. Suitable alkyl groups contain from 4 to50, preferably from 9 to 28 carbon atoms. Particularly suitable alkylgroups are C₁₂ groups derivable from propylene tetramer. The hydrocarbylsubstituted phenates are typically sulfurized.

According to one preferred embodiment of the present invention,overbased sulfurized alkylphenates of alkaline earth metals are preparedby neutralizing a sulfurized alkylphenol with an alkaline earth base inthe presence of a dilution oil, a glycol, and halide ions, the glycolbeing present in the form of a mixture with an alcohol having a boilingpoint above 150° C., removing alcohol, glycol, water, and sediment,carbonating the reaction medium with CO₂ in the presence of halide ions,and again removing alcohol, glycol, water, and sediment.

In another preferred embodiment, an overbased, sulfurized hydrocarbylphenate is prepared by a process comprising the steps of:

-   -   (a) neutralizing a sulfurized alkylphenol with an alkaline earth        base in the presence of a dilution oil, a glycol, and halide        ions, the glycol being present in the form of a mixture with an        alcohol having a boiling point above 150° C.;    -   (b) removing alcohol, glycol, and water from the medium,        preferably by distillation;    -   (c) removing sediment from the medium, preferably by filtration;    -   (d) carbonating the resultant medium with CO₂ in the presence of        halide ions; and    -   (e) removing alcohol, glycol, and water from the medium,        preferably by distillation.

The alkaline earth bases useful in the above process include the oxidesand hydroxides of barium, strontium, and calcium, particularly lime.Alcohols with a boiling point above 150° C. useful in the processinclude alcohols of C₅ to C₁₄ such as ethylhexanol, oxoalcohol,decylalcohol, tridecylalcohol; alkoxyalcohols such as 2-butoxyethanol,2-butoxypropanol; and methyl ethers of dipropylene glycol. The aminesuseful in the process include polyaminoalkanes, preferablypolyaminoethanes, particularly ethylenediamine, and aminoethers,particularly tris(3-oxa-6-amino-hexyl)amine. The glycols useful in theprocess include alkylene glycols, particularly ethylene glycol. Thehalide ions employed in the process are preferably Cl⁻ ions which may beadded in the form of ammonium chloride or metal chlorides such ascalcium chloride or zinc chloride.

The dilution oils suitable for use in the above process includenaphthenic oils and mixed oils and preferably paraffinic oils such asneutral 100 oil. The quantity of dilution oil used is such that theamount of oil in the final product constitutes from about 25% to about65% by weight of the final product, preferably from about 30% to about50%.

The process outlined above is more fully described in U.S. Pat. No.4,514,313, which is incorporated by reference into this application.

Preparation of Phenate-Carboxylates

The phenate-carboxylates which may be used in the present invention aretypically hydrocarbyl substituted phenate-carboxylates in which thehydrocarbyl substituent or substituents of the phenate are preferablyone or more alkyl group, either branched or unbranched. Suitable alkylgroups contain from 4 to 50, preferably from 9 to 28 carbon atoms.Particularly suitable alkyl groups are C₁₂ groups derivable frompropylene tetramer. The hydrocarbyl substituted phenate-carboxylates maybe sulfurized or unsulfurized.

The overbased hydrocarbyl phenate-carboxylate is prepared from anoverbased hydrocarbyl phenate which has been treated, either before,during, or subsequent to overbasing, with a long-chain carboxylic acid(preferably stearic acid), anhydride or salt thereof. That processcomprises contacting a mixture of a hydrocarbyl phenate, at least onesolvent, metal hydroxide, aqueous metal chloride, and an alkylpolyhydric alcohol containing from one to five carbon atoms, with carbondioxide under overbasing reaction conditions. Using an aqueous metalchloride, instead of a solid metal chloride, reduces the viscosity ofthe product. Preferably, the metals are alkaline earth metals, mostpreferably calcium. Preferably, the alkyl polyhydric alcohol is ethyleneglycol.

In a preferred embodiment, the overbased hydrocarbyl phenate-carboxylateis produced by overbasing a hydrocarbyl phenate and treating the phenate(before, during, or after overbasing) with a long-chain carboxylic acid(preferably stearic acid), anhydride or salt thereof.

In the overbasing step, a mixture comprising hydrocarbyl phenate (whichcan be sulfurized or unsulfurized), at least one solvent, metalhydroxide, aqueous metal chloride, and an alkyl polyhydric alcoholcontaining from one to five carbon atoms is reacted with carbon dioxideunder overbasing reaction conditions. Overbasing reaction conditionsinclude temperatures of from 250 to 375° F. at approximately atmosphericpressure.

Preferably, the overbased hydrocarbyl phenate is a sulfurizedalkylphenate. Preferably, the metal is an alkaline earth metal, morepreferably calcium. Preferably, the alkyl polyhydric alcohol is ethyleneglycol.

The carboxylate treatment (treatment with long-chain carboxylic acid,anhydride, or salt thereof) can occur before, during, or after theoverbasing step. It is unimportant when the treatment with long-chaincarboxylic acid, anhydride, or salt thereof occurs relative to theoverbasing step.

The phenate can be sulfurized or unsulfurized. Preferably, the phenateis sulfurized. If the phenate is sulfurized, the sulfurization step canoccur anytime prior to overbasing. More preferably, the phenate issulfurized before the overbasing step but after the carboxylatetreatment.

The process outlined above is more fully described in U.S. Pat. No.5,942,476, which is incorporated by reference into this application.

Preparation of Salicylates

The preparation of salicylates is well known in the art. Preferredsalicylates which may be used in the present invention include mediumand high overbased salicylates including salts of polyvalent ormonovalent metals, more preferably monovalent, most preferably calcium.As used herein, medium overbased (MOB) is meant to include salicylateswith a TBN of about 31 to 170. High overbased (HOB) is meant to includesalicylates with a TBN from about 171 to 400. High-hihg overbased (HHOB)is meant to include salicylates with a TBN over 400.

In one embodiment, salicylates may be prepared, for instance, startingfrom phenol, ortho-alkylphenol, or para-alkylphenol, by alkylation,carboxylation and salt formation. The alkylating agent preferably chosenis an olefin or a mixture of olefins with more than 12 carbon atoms tothe molecule. Acid-activated clays are suitable catalysts for thealkylation of phenol and ortho- and para- alkylphenol. The amount ofcatalyst employed is, in general, 1-10 wt %, in particular, 3-7 wt %,referred to the sum of the amounts by weight of alkylating agent andphenol to be alkylated. The alkylation may be carried out attemperatures between 100 and 250° C., in particular, between 125 and225° C.

The alkylphenols prepared via the phenol or ortho- or para-alkylphenolroute may be converted into the corresponding alkylsalicylic acids bytechniques well known in the art. For instance, the alkylphenols areconverted with the aid of an alcoholic caustic solution into thecorresponding alkylphenates and the latter are treated with CO₂ at about140° C. and a pressure of 10 to 30 atmospheres. From thealkylsalicylates so obtained, the alkylsalicylic acids may be liberatedwith the aid of, for example, 30% sulfuric acid.

For the preparation of overbased salicylates, the alkylsalicyclic acidsmay be treated with an excess amount of a metal compound, for instance,calcium in the form of Ca(OH)₂.

For example, the alkylsalicylic acids may be treated with 4 equivalentsof calcium in the form of Ca(OH)₂ with introduction of 1.6 equivalentsof CO₂.

The preparation of medium and overbased salicylates is more fullydescribed in U.S. Pat. No. 4,810,398, and GB Patents 1,146,925; 790,473;and 786,167, which are incorporated by reference into this application.

Preparation of Carboxy-Stearates

The carboxy-stearates which may be used in the present invention aretypically alkaline earth metal single-aromatic-ring hydrocarbylsalicylates that have been treated with a long-chain carboxylic acid,anhydride or salt thereof.

The carboxy-stearate is prepared from a mixture of alkaline earth metalsingle-aromatic-ring salicylate, at least one solvent, and alkalineearth metal hydroxide. The mixture is overbased by contacting themixture with carbon dioxide in the presence of an alkyl polyhydricalcohol, wherein the alkyl group of the alcohol has from one to fivecarbon atoms. One such useful alkyl polyhydric alcohol is ethyleneglycol.

The process outlined above is more fully described in U.S. Pat. No.6,348,438, which is incorporated by reference into this application.

Base Oil of Lubricating Viscosity

The base oil of lubricating viscosity used in such compositions may bemineral oil or synthetic oils of viscosity suitable for use in thecrankcase of an internal combustion engine. Crankcase base oilsordinarily have a viscosity of about 1300 cSt at 0° F. (−18° C.) to 3cSt at 210° F. (99° C.). The base oils may be derived from synthetic ornatural sources. Mineral oil for use as the base oil in this inventionincludes paraffinic, naphthenic and other oils that are ordinarily usedin lubricating oil compositions. Synthetic oils include both hydrocarbonsynthetic oils and synthetic esters. Useful synthetic hydrocarbon oilsinclude liquid polymers of alpha olefins having the proper viscosity.Especially useful are the hydrogenated liquid oligomers of C₆ to C₁₂alpha olefins such as 1-decene trimer. Likewise, alkyl benzenes ofproper viscosity, such as didodecyl benzene, can be used. Usefulsynthetic esters include the esters of monocarboxylic acids andpoolycarboxylic acids, as well as mono-hydroxy alkanols and polyols.Typical examples are didodecyl adipate, pentaerythritol tetracaproate,di-2-ethylhexyl adipate, dilaurylsebacate, and the like. Complex estersprepared from mixtures of mono and dicarboxylic acids and mono anddihydroxy alkanols can also be used.

Blends of mineral oils with synthetic oils are also useful. For example,blends of 10 to 25% hydrogenated 1-decene trimer with 75 to 90% 150 SUS(100° F.) mineral oil make excellent lubricating oil bases.

Other Additive Components

The following additive components are examples of some components thatcan be favorably employed in the present invention. These examples ofadditives are provided to illustrate the present invention, but they arenot intended to limit it:

-   -   (1) Ashless dispersants: alkenyl succinimides, alkenyl        succinimides modified with other organic compounds, and alkenyl        succinimides modified with boric acid, alkenyl succinic ester.    -   (2) Oxidation inhibitors:        -   (a) Phenol type oxidation inhibitors: 4,4′-methylene            bis(2,6-di-tert-butylphenol),            4,4′-bis(2,6-di-tert-butylphenol),            4,4′-bis(2-methyl-6-tert-butylphenol), 2,2′-methylene            bis(4-methyl-6-tert-butyl-phenol),            4,4′-butylidenebis(3-methyl-6-tert-butylphenol),            4,4′-isopropyl-idenebis(2,6-di-tert-butylphenol),            2,2′-methylene-bis(4-methyl-6-nonylphenol),            2,2′-isobutylidene-bis(4,6dimethyl-phenol),            2,2′-methylenebis(4-methyl-6-cyclohexylphenol),            2,6-di-tert-butyl4-methyl-phenol,            2,6-di-tert-butyl4-ethylphenol,            2,4-dimethyl-6-tert-butyl-phenol,            2,6-di-tert-4-(N,N′-dimethyl-aminomethylphenol),            4,4′-thiobis(2-methyl-6-tert-butylphenol),            2,2′-thiobis(4-methyl-6-tert-butylphenol),            bis(3-methyl4-hydroxy-5-tert-butylbenzylysulfide, and bis            (3,5-di-tert-butyl4-hydroxybenzyl).        -   (b) Diphenylamine type oxidation inhibitor: alkylated            diphenylamine, phenyl-alpha-naphthylamine, and alkylated            .alpha.-naphthylamine.        -   (c) Other types: metal dithiocarbamate (e.g., zinc            dithiocarbamate), molybdenum oxysulfide succinimide            complexes, and methylenebis (dibutyl-dithiocarbamate).    -   (3) Rust inhibitors (Anti-rust agents)        -   (a) Nonionic polyoxyethylene surface active agents:            polyoxyethylene lauryl ether, polyoxyethylene higher alcohol            ether, polyoxyethylene nonylphenyl ether, polyoxyethylene            octylphenyl ether, polyoxyethylene octyl stearyl ether,            polyoxyethylene oleyl ether, polyoxyethylene sorbitol            monostearate, polyoxyethylene sorbitol mono-oleate, and            polethylene glcol monooleate.        -   (b) Other compounds: stearic acid and other fatty acids,            dicarboxilic acids, metal soaps, fatty acid amine salts,            metal aalts of heavy sulfonic acid, partial carboxylic acid            ester of polyhydric alcohol, and phosphoric ester.    -   (4) Demulsifiers: addition product of alkylphenol and        ethyleneoxide, poloxyethylene alkyl ether, and polyoxyethylene        sorbitan ester.    -   (5) Extreme pressure agents (EP agents): zinc        dialkyldithiophosphate (aryl zinc, primary alkyl, and secondary        alkyl type), sulfurized oils, diphenyl sulfide, methyl        trichlorostearate, chlorinated naphthalene,        fluoroalkylpolysiloxane, and lead naphthenate.    -   (6) Friction modifiers: fatty alcohol, fatty acid, amine,        borated ester, and other esters.    -   (7) Multifunctional additives; sulfurized oxymolybdenum        dithiocarbamate, sulfurized oxymolybdenum organo phosphoro        dithioate, oxymolybdenum monoglyceride, oxymolybdenum diethylate        amide, amine-molybdenum complex compound, and sulfur-containing        molybdenym complex compound.    -   (8) Viscosity index improvers: polymethacrylate type polymers,        ethylene-propylene copolymers, styrene-isoprene copolymers,        hydrated styrene-isoprene copolymers, polyisobutylene, and        dispersant type viscosity index improvers.    -   (9) Pour point depressants: polymethyl methacrylate.    -   (10) Foam Inhibitors: alkyl methacrylate polymers and dimethyl        silicone polymers.    -   (11) Metal detergents: sulfurized or unsulfurized alkyl or        alkenyl phenates, alkyl or alkenyl aromatic sulfonates,        sulfurized or unsulfurized metal salts of multi-hydroxy alkyl or        alkenyl aromatic compounds, alkyl or alkenyl hydroxy aromatic        sulfonates, sulfurized or unsulfurized alkyl or alkenyl        naphthenates, metal salts of alkanoic acids, metal salts of an        alkyl or alkenyl multiacid, and chemical and physical mixtures        thereof.        Lubricating Oil Composition

The unsulfurized, carboxylate-containing additive produced by theprocess of this invention is useful for imparting detergency to anengine lubricating oil composition. Such a lubricating oil compositioncomprises a major part of a base oil of lubricating viscosity and aneffective amount of the unsulfurized, carboxylate-containing additive ofthe present invention, typically from about 1% to about 30% by weight,based on the total weight of the lubricating oil composition.

Adding an effective amount the unsulfurized, carboxylate-containingadditive of the present invention to a lubricating oil improves thedetergency of that lubricating oil in automotive diesel and gasolineengines, as well as in marine engine applications. Such compositions arefrequently used in combination with Group II metal detergents, and otheradditives.

Lubricating marine engines with an effective amount of lubricating oilhaving the unsulfurized, carboxylate-containing additive of the presentinvention can control black sludge deposits. It also improves the hightemperature deposit control performance and demulsibility performance ofthat lubricating oil in marine applications.

Adding an effective amount of the unsulfurized, carboxylate-containingadditive of the present invention to a lubricating oil improves the hightemperature deposit control performance, corrosion control and theoxidation inhibition performance of that lubricating oil in automotiveapplications.

In one embodiment, an engine lubricating oil composition would contain

-   -   (a) a major part of a base oil of lubricating viscosity;    -   (b) 1% to 30% of the unsulfurized, carboxylate-containing        additive of the present invention;    -   (c) 0% to 20% of at least one ashless dispersant;    -   (d) 0% to 5% of at least one zinc dithiophosphate;    -   (e) 0% to 10% of at least one oxidation inhibitor;    -   (f) 0% to 1% of at least one foam inhibitor; and    -   (g) 0% to 20% of at least one viscosity index improver.

In another embodiment, an engine lubricating oil composition wouldcontain the above components and from 0% to 30% of a metal-containingdetergent.

In a further embodiment, an engine lubricating oil composition isproduced by blending a mixture of the above components. The lubricatingoil composition produced by that method might have a slightly differentcomposition than the initial mixture, because the components mayinteract. The components can be blended in any order and can be blendedas combinations of components.

Hydraulic Oil Composition

A hydraulic oil composition having improved filterability can be formedcontaining a major part of a base oil of lubricating viscosity, from0.1% to 6% by weight of the unsulfurized, carboxylate-containingadditive of the present invention, and preferably at least one otheradditive.

Additive Concentrates

Additive concentrates are also included within the scope of thisinvention. The concentrates of this invention comprise the compounds orcompound mixtures of the present invention, with at least one of theadditives disclosed above. Typically, the concentrates containsufficient organic diluent to make them easy to handle during shippingand storage.

From 20% to 80% of the concentrate is organic diluent. From 0.5% to 80%of the concentrate is the unsulfurized, carboxylate-containing additiveof the present invention. The unsulfurized, carboxylate-containingadditive contains the single-aromatic-ring hydrocarbyl salicylate, andpossibly hydrocarbyl phenol and hydrocarbyl phenate. The remainder ofthe concentrate consists of other additives.

Suitable organic diluents that can be used include mineral oil orsynthetic oils, as described above in the section entitled “Base Oil ofLubricating Viscosity.” The organic diluent preferably has a viscosityof from about 1 to about 20 cSt at 100° C.

Examples of Additive Packages

Below are representative examples of additive packages that can be usedin a variety of applications. These representative examples employ theunsulfurized, carboxylate-containing additive of the present invention.The unsulfurized, carboxylate-containing additive contains thesingle-aromatic-ring hydrocarbyl salicylate, and possibly hydrocarbylphenol and hydrocarbyl phenate. The unsulfurized, carboxylate-containingadditive may be used either with or without other metal-containingdetergents, depending upon the desired BN of the final product. Thefollowing percentages are based on the amount of active component, withneither process oil nor diluent oil, but including sufficientmetal-containing detergents (including other types of metal detergents)to achieve the desired BN. These examples are provided to illustrate thepresent invention, but they are not intended to limit it. I. MarineDiesel Engine Oils 1) Unsulfurized, carboxylate-containing additive 65%Primary alkyl zinc dithiophosphate 5% Oil of lubricating viscosity 30%2) Unsulfurized, carboxylate-containing additive 65% Alkenyl succinimideashless dispersant 5% Oil of lubricating viscosity 30% 3) Unsulfurized,carboxylate-containing additive 60% Primary alkyl zinc dithiophosphate5% Alkenyl succinimide ashless dispersant 5% Oil of lubricatingviscosity 30% 4) Unsulfurized, carboxylate-containing additive 65%Phenol type oxidation inhibitor 10% Oil of lubricating viscosity 25% 5)Unsulfurized, carboxylate-containing additive 55% Alkylateddiphenylamine-type oxidation inhibitor 15% Oil of lubricating viscosity30% 6) Unsulfurized, carboxylate-containing additive 65% Phenol-typeoxidation inhibitor 5% Alkylated diphenylamine-type oxidation inhibitor5% Oil of lubricating viscosity 25% 7) Unsulfurized,carboxylate-containing additive 60% Primary alkyl zinc dithiophosphate5% Phenol-type oxidation inhibitor 5% Oil of lubricating viscosity 30%8) Unsulfurized, carboxylate-containing additive 60% Alkenyl succinimideashless dispersant 5% Alkylated diphenylamine-type oxidation inhibitor10% Oil of lubricating viscosity 25% 9) Unsulfurized,carboxylate-containing additive 55% Other additives 25% Primary alkylzinc dithiophosphate Alkenyl succinic ester ashless dispersantPhenol-type oxidation inhibitor Alkylated diphenylamine-type oxidationinhibitor Oil of lubricating viscosity 30%

II. Motor Car Engine Oils 1) Unsulfurized, carboxylate-containingadditive 25% Alkenyl succinimide ashless dispersant 35% Primary alkylzinc dithiophosphate 10% Oil of lubricating viscosity 30% 2)Unsulfurized, carboxylate-containing additive 20% Alkenyl succinimideashless dispersant 40% Secondary alkyl zinc dithiophosphate 5%Dithiocarbamate type oxidation inhibitor 5% Oil of lubricating viscosity30% 3) Unsulfurized, carboxylate-containing additive 20% Alkenylsuccinimide ashless dispersant 35% Secondary alkyl zinc dithiophosphate5% Phenol type oxidation inhibitor 5% Oil of lubricating viscosity 35%4) Unsulfurized, carboxylate-containing additive 20% Alkenyl succinimideashless dispersant 30% Secondary alkyl zinc dithiophosphate 5%Dithiocarbamate type anti-wear agent 5% Oil of lubricating viscosity 40%5) Unsulfurized, carboxylate-containing additive 20% Succinimide ashlessdispersant 30% Secondary alkyl zinc dithiophosphate 5%Molybdenum-containing anti-wear agent 5% Oil of lubricating viscosity40% 6) Unsulfurized, carboxylate-containing additive 20% Alkenylsuccinimide ashless dispersant 30% Other additives 10% Primary alkylzinc dithiophosphate Secondary alkyl zinc dithiophosphate Alkylateddiphenylamine-type oxidation inhibitor Dithiocarbamate type anti-wearagent Oil of lubricating viscosity 40% 7) Unsulfurized,carboxylate-containing additive 60% Other additives 10% Phenol typeoxidation inhibitor Alkylated diphenylamine-type Oxidation inhibitorDithiocarbamate type anti-wear agent Demulsifier Boron-containingfriction modifier Oil of lubricating viscosity 30%

III. Hydraulic Oils 1) Unsulfurized, carboxylate-containing additive 20%Primary alkyl zinc dithiophosphate 50% Other additives 25% Phenol typeoxidation inhibitor Phosphorus-containing extreme pressure agent Triazoltype corrosion inhibitor Demulsifier Nonionic anti-rust agent Oil oflubricating viscosity 5% 2) Unsulfurized, carboxylate-containingadditive 10% Primary alkyl zinc dithiophosphate 40% Other additives 47%Phenol type oxidation inhibitor Sulfur-containing extreme pressure agentTriazol type corrosion inhibitor Demulsifier Nonionic anti-rust agentOil of lubricating viscosity 3% 3) Unsulfurized, carboxylate-containingadditive 10% Phosphorus-containing extreme pressure agent 40% Phenoltype oxidation inhibitor 15% Other additives 25% Diphenylamine typeoxidation inhibitor Sulfur-containing extreme pressure agent Triazoltype corrosion inhibitor Demulsifier Nonionic anti-rust agent Oil oflubricating viscosity 10% 4) Unsulfurized, carboxylate-containingadditive 20% Phosphorus-containing extreme pressure agent 30% Otheradditives 45% Diphenylamine type oxidation inhibitor Sulfur-containingextreme pressure agent Triazol type corrosion inhibitor DemulsifierNonionic anti-rust agent Oil of lubricating viscosity 5%

IV. Transmission Hydraulic Fluids 1) Unsulfurized,carboxylate-containing additive 35% Primary alkyl zinc dithiophosphate20% Polyol type friction modifier 20% Sulfur-containing extreme pressureagent 5% Oil of lubricating viscosity 20% 2) Unsulfurized,carboxylate-containing additive 40% Primary alkyl zinc dithiophosphate15% Amide type friction modifier 15% Sulfur-containing extreme pressureagent 5% Oil of lubricating viscosity 25% 3) Unsulfurized,carboxylate-containing additive 30% Primary alkyl zinc dithiophosphate20% Other additives 30% Alkenyl succinimide ashless dispersant Amidetype friction modifier Ester type friction modifier Phosphorus,Sulfur-containing extreme pressure agent Oil of lubricating viscosity20% 4) Unsulfurized, carboxylate-containing additive 35% Primary alkylzinc dithiophosphate 15% Other additives 25% Polyol type frictionmodifier Amide type friction modifier Phosphorus, Sulfur-containingextreme pressure agent Oil of lubricating viscosity 25%

EXAMPLES

The invention will be further illustrated by following examples, whichset forth particularly advantageous method embodiments. While theExamples are provided to illustrate the present invention, they are notintended to limit it.

Example 1

Preparation of the Novel Unsulfurized, Carboxylate-Containing Additive

An intermediate product was prepared according to the procedure given inU.S. Pat. No. 6,162,770, Example 1. Said procedure is reproduced here:

A. Neutralization

A charge of 875 g of branched dodecylphenol (DDP) having a molecularmass of 270, (i.e. 3.24 moles) and 875 g of linear alkylphenol having amolecular mass of about 390 (i.e. 2.24 moles) was placed in afour-necked 4 liter glass reactor above which was a heat-insulatedVigreux fractionating column. The isomeric molar repartition of paraversus ortho alkylphenol was:

DDP: 89% para and 5.5% ortho

Linear alkylphenol: 39% para and 53% ortho.

The agitator was started up and the reaction mixture was heated to 65°C., at which temperature 158 grams of slaked lime Ca(OH)₂ (i.e. 2.135moles) and 19 g of a mixture (50/50 by weight) of formic acid and aceticacid were added.

The reaction medium underwent further heating to 120° C. at whichtemperature the reactor was placed under a nitrogen atmosphere, thenheated up to 165° C. and then the nitrogen introduction was stopped.Distillation of water commenced at this temperature.

The temperature was increased to 240° C. and the pressure was reducedgradually below atmospheric until an absolute pressure of 5,000 Pa (50mbars) was obtained.

The reaction mixture was kept for five hours under the precedingconditions. The reaction mixture was allowed to cool to 180° C., thenthe vacuum was broken under a nitrogen atmosphere and a sample was takenfor analysis. The total quality of distillate obtained was about 120cm³; demixing took place in the lower phase (66 cm³ being water).

B. Carboxylation:

The product obtained in Step (A) was transferred to a 3.6-literautoclave and heated to 180° C.

At this temperature, scavenging of the reactor with carbon dioxide (CO₂)was commenced and continued for ten minutes. The amount of CO₂ used inthis step was in the order of 20 grams.

After the temperature had been raised to 200° C., the autoclave wasclosed, leaving a very small leak, and the introduction of CO₂ wascontinued so as to maintain a pressure of 3.5×10⁵ Pa (3.5 bars) for 5hours at 200° C. The amount of CO₂ introduced was in the order of 50grams. After the autoclave had been cooled to 165° C., the pressure wasrestored to atmospheric and the reactor was then purged with nitrogen.

A total quality of 1,912 grams of product was recovered prior tofiltration. The product was then filtered.

The above procedure was scaled up to a 6000 gallon reactor and used toprepare the intermediate product. The intermediate product was thensubjected to the additional step of distillation outlined below.

Analytical results for the intermediate product from the 6000 gallonbatc were as follows: TBN  116 mg KOH/gm Calcium  4.1 wt % SalicylicAcid Index (SAI)   40 mg KOH/gm

SAI is a measure of the quantity of alkylsalicylate formed in thedetergent-dispersant. It was determined by acidification of the productby a strong acid (hydrochloric acid) in the presence of diethyl ether,followed by a photentiometric titration on the organic fraction (tetran-butyl ammonium hydroxide was used as a titration agent). Results areexpressed in equivalent mg KOH per gram of product (Base Number unit).

Distillation:

The intermediate product was fed at a rate of 70 kg/hr to a wiped filmevaporator (WFE) which had a surface area of 0.39 m². The WFE had aninternal condenser and entrainment separator along with a hot oiljacket. The hot oil temperature in the jacket was about 250° C. Thepressure within the WFE was 1.3 mbar. The feed temperature to the WFEwas 135° C. Final product temperature exiting the WFE was 222° C. Theproduct was cooled to less than 100° C. before dilluting with 100N baseoil. Approximately 47.5% (by weight) of the feed to the WFE wascollected as distillate. The amount of distillate collected may varyfrom 10% up to about 55% by weight of the feed to the WFE. Dependingupon the level of distillation, enough organic dilluent is then added tothe distilled product to give a manageable viscosity. As the weightpercentage of feed collected as distillate increases, the amount ofdiluent needed to be added to the distilled product in order to give amanageable viscosity increases.

Analytical results for the distilled product were as follows: TBN 174 mgKOH/gm Ca 6.09 wt % Salicylic Acid Index (SAI) 58 Viscosity at 100° C.705 cSt Oil Content (by mass balance) 21.5 wt %

It is well known in the art that salicylate structures are thermallyunstable. As the distilled material had a comparable Salicylic-Acidindex to calcium ratio as the feedstock, no decomposition of thesalicylate structure occurred even though the feed was exposed torelatively high temperatures. No decomposition occurred as the reductiontime in the WFE is relatively short.

The distillate appearance was clear and slightly yellow which iscomparable to the appearance of the starting hydrocarbyl phenolsintroduced in the neutralization step. The TBN content of the distillatewas essentially zero indicating than none of the feedstock to thedistillation step carried over into the distillate. The distillate wasanalyzed by gas chromatography and found to contain approximately 61%branched hydrocarbyl phenol, 39% linear hydrocarbyl phenol, and 6% 100Nbase oil.

Example 2

The pre-distillation product prepared according to Example 1 wasdistilled under various conditions in the WFE described above. Typicalresults for other distillation conditions are shown in Table 1. TABLE 11 2 WFE Conditions: Feed Rate (kg/hr) 122 86 Pressure (mbar) 1.44 1.5Hot Oil Temp (° C.) 235 254 Product Temperature Exiting 205 222Evaporator (° C.) Amount of Distillate (wt %)¹ 30 43 Oil in FinalProduct (wt %) 0 14.5 Product Analytical Results TBN (mg KOH/gm) 166 174Ca (wt %) 5.92 6.2 SAI (mg KOH/gm) 57 59 Viscosity @ 100° C. (cSt) 226575 Compostion of Distillate Branched Alkylphenol (wt %) 76 64 LinearAlkylphenol (wt %) 15 27 100N Base Oil (wt %) 9 9¹Based on WFE Feed Rate

Example 3

Example 1 was repeated except for the following changes:

-   -   a) The WFE had a surface area of 0.78 m²    -   b) The feed rate to the WFE was about 135 kg/hr    -   c) The final distilled product was diluted with about 36 wt %        100N oil to produce a product with a manageable viscosity.

Similar to Example 1, about 46% (based on weight) of the feed to theevaporator was collected as distillate.

Analytical results for this product are as follows: TBN  138 mg KOH/gmCalcium 4.96 wt % SAI   47 mg KOH/gm

Dialysis was performed on about 15 gm of product from Example 3 using aSoxhlet extraction apparatus (pentane solvent) and a Latex membranecondom for about 24 hours to afford a dialysate fraction (the materialthat passes through the membrane) and a residue fraction (the materialleft in the latex membrane bag).

The dialysate fraction from the dialysis procedure was separated intotwo fractions using silica gel chromatography (0.2-0.25 gm on two SilicaGel Cartridges—Waters Part No. 051900) first using 12 ml of hexane toyield Fraction 1 followed by reversing the Cartridges and flushing with12 ml of 80:20 Ethyl Acetate: Ethanol to afford Fraction 2. Fraction 1was comprised of diluent oil and Fraction 2 was comprised of freealkylphenols.

The Fraction 2 obtained from the chromatographic separation procedurewas analyzed using supercritical chromatography (SFC) to determine theamount of branched alkylphenol and linear alkylphenol present.Quantification was performed using a calibration curve of known mixturesof branched and linear alkylphenol.

% SA was determined on the dialysis residue fraction by acidification ofthe product by a strong acid (hydrochloric acid) in the presence ofdiethyl ether, followed by a potentiometric titration on the organicfraction (tetra n-butyl ammonium hydroxide was used as a titrationagent). This method separates and quantifies the alkyl salicylic acidand the remaining alkylphenol (non-carboxylated alkylphenate). Resultswere expressed in equivalent mg KOH per gram of product (Base Numberunit). % SA was then determined by using the following equation:% SA=100*(Alkylsalicylic acid(Alkylphenol+Alkylsalicylic acid))% Ca in the residue was determined by classical X Ray spectrometry.

Dialysis results are as follows: Dialysate 51.1 wt % of starting sampleweight Residue 48.9 wt % of starting sample weight

Dialysate Composition: Dodecylphenol  1.0 wt % Linear Alkylphenol 26.7wt % 100N Base Oil 72.3 wt %

Residue Composition Calcium  9.3 wt % TBN  259 mg KOH/gm SAI   78 mgKOH/gm % SA   50

The following composition of the product produced in Example 3 wascalculated from the composition of the dialysate and residue fractions:Total Alkylphenol Content 14.1 wt % Oil 36.9 wt % Single Aromatic RingAlkylsalicylate 24.5 wt % Calcium Alkylphenate 24.5 wt %Procedures for Performance Tests

The following Section described Performance Test Methods referred to inthese examples.

Bulk Oxidation (MIP-48)

The Modified IP-48 test (or MIP-48 test) is a bulk oil oxidation test.The IP-48 test is test method 48 of the institute of Petroleum and canbe found in “Standard methods for analysis and testing of petroleum andrelated products and British Standard 2000 parts, 2000, MethodsIP-1-324, Volume 1” published on behalf of the institute of petroleum(London) by John Wiley & Sons, LTD (Chisester, New York, Weinheim,Brisbane, Singapore, Toronto). In said test, air is bubbled through alubricant sample which is kept at high temperature. The viscosity of theend-of-test sample is compared to that of a reference sample which hsthe exact same composition but is bubbled through with nitrogen. The netviscosity increase (expressed as a percentage increase) is an indicationfor the oxidation stability of a lubricant. The lower the viscosityincrease, the better.

Corrosion Control (ASTM D6594-01)

This is a standard test method for evaluation of corrosiveness of dieselengine oil at 135° C. This test method is used to test diesel enginelubricants to determine their tendency to corrode various metals,specifically alloys of lead and copper commonly used in cam followersand bearings. Four metal specimens of copper, lead, tin, and phosphorbronze are immersed in a measured amount of engine oil. The oil, at anelevated temperature, is blown with air for a period of time. When thetest is completed, the copper specimen and the stressed oil are examinedto detect corrosion and corrosion products, respectively.

Examples Showing Performance Advantages

The following Examples illustrate performance advantages demonstrated bylubricating oil compositions containing the unsulfurizedcarboxylate-containing additive of the present invention.

Example 4

Marine Engine Oils Performance

The lubrication oil formulations used in the present example weregenerated for lubricants intended for use in Marine Trunk Piston Enginesand had the following compositions: Formula 1 Phenate-Stearate 6.04%Zinc Dithiophosphate 0.64% Foam Inhibitor 0.04% Commercialdetergent-dispersant 14.72%

Formula 1A Phenate-Stearate 6.04% Zinc Dithiophosphate 0.64% FoamInhibitor 0.04% Unsulfurized, carboxylate-containing additive 10.17%prepared according to Example 1

Formula 2 Phenate 7.22% Zinc Dithiophosphate 0.64% Foam Inhibitor 0.04%Commercial detergent-dispersant 16.83%

Formula 2A Phenate 7.22% Zinc Dithiophosphate 0.64% Foam Inhibitor 0.04%Unsulfurized, carboxylate-containing additive 11.05% prepared accordingto Example 1

Formula 3 HOB Salicylate 8.93% Zinc Dithiophosphate 0.64% Foam Inhibitor0.04% MOB Salicylate 8.88%

Formula 3A HOB Salicylate 8.93% Zinc Dithiophosphate 0.64% FoamInhibitor 0.04% Unsulfurized, carboxylate-containing additive 8.72%prepared according to Example 1

Formula 4A Carboxy-Stearate 8.83% Zinc Dithiophosphate 0.64% FoamInhibitor 0.04% Unsulfurized, carboxylate-containing additive 8.72%prepared according to Example 1

The treat rates of these concentrated additives in finished oil wereadjusted to ensure a BN of 40 mg KOH/g according to ASTM D2896 for thefinished lubricant. Results of Bulk Oxidation Test For- mula FormulaFormula Formula Formula Formula Formula 1 1A 2 2A 3 3A 4A MIP-48 39 1745 25 24 22 20 results

The results of the MIP-48 bulk oxidation test show that theunsulfurized, carboxylate-containing additive of the present inventionhas surprisingly better viscosity increase control (VIC) compared to acommercial detergent-dispersant when tested at the same BN level in thesame formulation.

Example 5

Automotive Performance

The lubrication oil formulations used in the present example weredesigned for Low Emission Diesel Lubricants (LEDL) intended for use inLow Emission Diesel Engines and had the following compositions: BaselineFormulation A A B B C C Sulfated Ash, % 0.95 0.95 1.0 1.0 1.0 1.0Sulphur, % 0.10 0.10 0.12 0.12 0.10 0.10 Phosphorus, % 0.05 0.05 0.050.05 0.05 0.05 Borated Dispersant Y Y Y Y Y Y Non-Borated Dispersant Y YY Y Y Y LOB Ca-Sulfonate N N Y Y N N LOB Salicylate N N N N Y YCommercially Available Salicylate, wt % 4.5 N 4.5 N 4.5 N Unsulfurized,carboxylate-containing additive N 5.0 N 5.0 N 5.0 prepared according toExample 1 Secondary ZnDTP Y Y Y Y Y Y Diphenylamine Anti-Oxidant Y Y Y YY Y Molybdenum Anti-Oxidant Y Y Y Y Y Y Foam Inhibitor Y Y Y Y Y Y OCPVII Y Y Y Y Y Y Base Oil 1 Y Y Y Y Y Y Base Oil 2 Y Y Y Y Y Y HTCBT 11860 140 74 230 108 Pb, ppm

For each formulation, the unsulfurized, carboxylate-containing additiveof the present invention was compared to a commercially availablesalicylate for corrosion performance. In each case, covering a range ofsulfur, phosphorus and ash levels, the carboxylate-containing additiveof the present invention displayed superior corrosion controlperformance.

While the present invention has been described with reference tospecific embodiments, this application is intended to cover thosevarious changes and substitutions that may be made by those skilled inthe art without departing from the spirit and scope of the appendedclaims.

1-41. (canceled)
 42. A lubricating oil additive comprising: (a) from 0to 35% hydrocarbyl phenol; (b) from 10 to 50% alkaline earth metalhydrocarbyl phenate; (c) from 15 to 60% alkaline earth metalsingle-aromatic-ring hydrocarbyl salicylate; and (d) from 0% to 50%organic diluent.
 43. A lubricating oil additive according to claim 42further comprising an alkaline earth double-aromatic-ring hydrocarbylsalicylate wherein the mole ratio of single-aromatic-ring hydrocarbylsalicylate to double-aromatic-ring hydrocarbyl salicylate is at least8:1.
 44. A lubricating oil composition comprising: (a) a major part of abase oil of lubricating viscosity, (b) from 1% to 30% of the lubricatingoil additive according to claim
 42. 45. A lubricating oil compositionaccording to claim 44 further comprising at least one of the following:(a) an ashless dispersant (b) an oxidation inhibitor; (c) a rustinhibitor; (d) a demulsifier; (e) an extreme pressure agent; (f) afriction modifier; (g) a multifunctional additive; (h) a viscosity indeximprover; (i) a pour point depressant; (j) a foam inhibitor; and (k) ametal-containing detergent.
 46. A hydraulic oil composition containing amajor part of base oil of lubricating viscosity and from 0.1 to 6.0% ofthe lubricating oil additive according to claim
 42. 47. A concentratecomprising: a) from 20 to 80% of an organic diluent, and (b) thelubricating oil additive according to claim
 42. 48. An additive packagecomprising the lubricating oil additive according to claim 42 andfurther comprising at least one of the following: (a) a metal-containingdetergent (b) an ashless dispersant (c) an oxidation inhibitor; (d) arust inhibitor; (e) a demulsifier; (f) an extreme pressure agent; (g) afriction modifier; (h) a multifunctional additive; (i) a viscosity indeximprover; (j) a pour point depressant; and (k) a foam inhibitor.
 49. Alubricant additive composition comprising the lubricating oil additiveof claim 42 and at least one of the following: (a) a phenate; (b) aphenate-stearate; (c) a salicylate; and (d) a carboxy-stearate.
 50. Thecomposition of claim 49 wherein the mass ratio of phenate to saidlubricating oil additive is from 1:0.035 to 1:98.
 51. The composition ofclaim 49 wherein the mass ratio of phenate to said lubricating oiladditive is from 1:0.239 to 1:14.
 52. The composition of claim 49wherein the mass ratio of phenate to said lubricating oil additive isfrom 1:0.451 to 1:7.5.
 53. The composition of claim 49 wherein the massratio of phenate-stearate to said lubricating oil additive is from1:0.051 to 1:126.
 54. The composition of claim 49 wherein the mass ratioof phenate-stearate to said lubricating oil additive is from 1:0.353 to1:18.
 55. The composition of claim 49 wherein the mass ratio ofphenate-stearate to said lubricating oil additive is from 1:0.667 to1:9.7.
 56. The composition of claim 49 wherein said salicylate is amedium-overbased salicylate.
 57. The composition of claim 49 whereinsaid salicylate is a high-overbased salicylate.
 58. The composition ofclaim 57 wherein the mass ratio of salicylate to said lubricating oiladditive is from 1:0.026 to 1:120.
 59. The composition of claim 57wherein the mass ratio of salicylate to said lubricating oil additive isfrom 1:0.178 to 1:17.
 60. The composition of claim 57 wherein the massratio of salicylate to said lubricating oil additive is from 1:0.335 to1:9.2.
 61. The composition of claim 49 wherein the mass ratio ofcarboxy-stearate to said lubricating oil additive is from 1:0.023 to1:105.
 62. The composition of claim 49 wherein the mass ratio ofcarboxy-stearate to said lubricating oil additive is from 1:0.156 to1:15.
 63. The composition of claim 49 wherein the mass ratio ofcarboxy-stearate to said lubricating oil additive is from 1:0.294 to1:8.1.
 64. A method for improving corrosion protection in an internalcombustion engine, said method comprising operating an internalcombustion engine with the lubricating oil composition according toclaim
 44. 65. A method for improving viscosity increase control of alubricating oil composition, said method comprising adding an effectiveviscosity increase controlling amount of the lubricating oil additivecomposition according to claim 42 to said lubricating oil composition.66. (canceled)